I have to say, I think all the articles about if you never buy the latte on the way to work or those set of things are really inane and silly in terms of being the key to "saving money" or "becoming rich".
They extrapolate out ridiculous statistics and tell you how you'd be a multi-millionaire by just making this one change.
What is usually emphasized is the "don't buy the coffee". What needs to be emphasized, and understood is the need for you to increase what you are investing or saving. To top it off, most people who have that as a "habit" will not buy the coffee some days, but buy the coffee other days. They turn personal finance into the diet with "cheat days" instead of a permanent lifestyle change.
Also, finding ways to say, live in a smaller home, drive a smaller car, make sure your energy bill isn't $600 a month, etc. are going to make it much easier from a financial standpoint - cutting the BIG expenses, and doing it ONCE, not every day. Even something like getting rid of your cable tv I think might help even more because while it might be a similar amount for the cost of the lattes M-F, you only have to make that choice ONCE, not constantly.
That said, I don't ever stop and get coffee on the way to work, so maybe I'm just bitter that I can't become a multimillionaire with this "life hack"...